The present invention relates to a method of manufacturing an electronic component, particularly to a method of manufacturing an electronic component having a structure in which a cover material, such as an insulating film or a protective film, is disposed to cover an entire surface of the electronic component except for locations at which cutting lines intersect.
2. Description of Prior Art
For example, as shown in FIG. 5, a chip type coil component includes a thin film coil pattern (conductor pattern) which is disposed on a surface of a substrate. The method of manufacturing such a chip type coil component includes a step of cutting out individual elements 54 by cutting a mother substrate 53 on which a plurality of thin film coil patterns 51 are arranged. As can be seen in FIG. 5, the surfaces of the thin film coil patterns 51 are covered with an insulating/protecting film (referred to as a xe2x80x9ccover materialxe2x80x9d) 52 at predetermined positions.
Further, a resin material including, for example, polyimide or the like is used for the cover material 52 because of its desired surface smoothness, insulation performance, heat resistance and aptitude for micro-machining required because of the decreasing size of such components.
Further, a conventional method of cutting out the individual elements 54 by cutting the mother substrate 53 at predetermined positions includes a step of breaking the mother substrate 53 by using a scriber. However, this method requires a process of cutting and separating each element 54 from the mother substrate 53 by using a cleavage operation. With such a method, the mother substrate 53 cannot be cut when the insulating/protecting film 52 covers scribe lines. Therefore, cut margins 55 shown in FIG. 5 must be provided at the periphery of each of the insulating/protecting films 52.
Further, considering the machining accuracy of the scribing and breaking process involved in this conventional method, a width of the cut margin 55 provided at the periphery of the insulating/protecting film 52 needs to be at least about 100 xcexcm and each insulating/protecting film 52 needs to be located at a region about 50 xcexcm from respective surrounding peripheral portions of each individual element 54, such as a thin film coil pattern.
Further, considering the forming accuracy of the insulating/protecting films 52, the thin film coil pattern (conductor pattern) 51 needs to be formed about 30 to 50 xcexcm from respective surrounding peripheral portions of the insulating/protecting film 52.
When it is necessary to reduce a size of an electronic component of a chip type, particularly, a chip type coil component including a conductive pattern comprising a thin film coil pattern or the like located on the surface of a substrate, is important to have a sufficient width and size of an area for forming a conductive pattern in order to maintain and improve the function and characteristics of the component. However, when a mother substrate is cut by the scribing and breaking process as described above, it is difficult to secure an area on the mother substrate that is sufficient for forming a conductive pattern because of problems with the manufacturing accuracy of the scribing and breaking process and accuracy of forming the insulating/protecting film. Thus, it is not possible to achieve the desired reduction in size of the electronic component.
Further, other conventional methods of cutting out individual elements by cutting the mother substrate at predetermined positions involve a dicing process using a dicing blade for cutting the mother substrate. According to such a dicing process, the manufacturing accuracy is improved and the insulating/protecting film can simultaneously be cut with the substrate. Therefore, the cut margin 55 required in the method shown in FIG. 5 is not needed. Thus, as shown in FIG. 6, the insulating/protecting film 52 can be formed on the entire surface of the mother substrate 53 and there is no requirement to leave exposed portions of the substrate or to form cut margins 55 required in the process shown in FIG. 5. Accordingly, this conventional method using a dicing process provides an advantage over the scribing and breaking process or the like shown in FIG. 5, because in the conventional method shown in FIG. 6, the conductor patterns 51 can extend up to the outer peripheral portions of a chip and an area which can be used for forming the chip can be reliably and accurately provided.
According to the conventional dicing process, the mother substrate 53 is cut along cut lines A and B (FIG. 6) which intersect each other perpendicularly. In that case, for example, a first cutting operation is initially performed along the cut lines A and a second cutting operation is performed thereafter along the cut lines B of a sub-mother substrate 53a having a strip-like shape to thereby cut out the individual elements 54 from the substrate 53.
Further, in performing the second cutting operation, the dicing blade is always brought into contact with an end of the substrate (end portion of the sub-mother substrate 53a which is formed to have the strip-like shape by the first cutting operation). At this moment, as shown by FIG. 7, the machining is performed by first bringing the insulating/protecting film 52 into contact with the dicing blade 57 at an end portion of the sub-mother substrate 53a. The insulating/protecting film 52 is sing softer and more deformable than a material used for forming the substrate. A very small chip or breakage of the insulating/protecting film 52 is liable to occur at the end portion of the sub-mother substrate 53a during dicing because of the action of the dicing blade 57 on the substrate 53a. Therefore, debris 56 comprising a part of the insulating/protecting film 52 may be caused at the end of the substrate 53a by stretching or removal of the insulating/protecting film 52 or may remain in the individual elements 54 of the electronic component.
A product where debris from the insulating/protecting film remains on the component as described above, causes a failure in the functioning and reliability of the electronic component and the finished product incorporating the electronic component.
To overcome the problems described above, the preferred embodiments of the present invention provide a method of manufacturing an electronic component which is arranged to increase an area on a surface of a mother substrate which is available for forming an element of the electronic component while preventing debris from an insulating/protecting film from remaining on the element or the electronic component.
According to one preferred embodiment of the present invention, there is provided a method of manufacturing an electronic component which includes the steps of providing a mother substrate; forming a plurality of elements of the electronic component on the mother substrate; forming a cover material, such as an insulating film or a protecting film, on an entire surface of the mother substrate except for locations where cutting lines intersect such that portions of the substrate are exposed only at the locations where the cutting lines intersect; cutting out a plurality of the elements of the electronic component from the mother substrate by cutting the mother substrate along the intersecting cut lines; wherein the mother substrate is cut along the cut lines by using a dicing process and the dicing process begins at the exposed portions of the substrate where cutting lines intersect such that only the mother substrate is cut initially and then continues such that the mother substrate and the cover material are cut together.
By cutting the mother substrate where the cover material is not located at portions of intersecting cut lines such that the surface of the mother substrate is exposed at the intersection portions, several advantages are provided. When a first cutting operation is performed initially along cut lines A and thereafter, and a second cutting operation is performed along cut lines B with respect to a sub-mother substrate 3a having a strip-like shape as shown by FIG. 1, end portions (intersection portions 5) of the mother substrate 3 and sub-mother substrate 3a are the first portions of the mother substrate 3 and sub-mother substrate 3a contacted by a dicing blade 6. Because these portions of the mother substrate 3 and sub-mother substrate are not covered with a cover material (insulating/protecting film) 2, the cover material 2 is not pulled or deformed by the dicing blade G. After a portion (exposed portion 5a) of the mother substrate 3 and sub-mother substrate 3a that is not covered with the cover material 2 has been cut as shown by FIG. 2(a), successively, as shown by FIG. 2(b), the cover material 2 and the mother substrate and the cover material and the sub-mother substrate 3a are simultaneously cut (machined). Therefore, individual elements of the electronic component can be accurately and reliably cut out by firmly cutting the mother substrate without causing or leaving debris of the cover material.
According to the preferred embodiments of the present invention, not only the intersection portions 5 of the cut lines A and B but the surface of the mother substrate 3 can be exposed also at end portions of the cut lines A which are to be cut in the first cutting step.
With the above described method, it is possible to form a cover material over an entire surface of a mother substrate, except for locations at which the cutting lines intersect. Thus, it is not required to form cut margins 55 as shown in FIG. 5 or have the required exact separation of the elements 51 from other elements 51 and from cut margins 55. Thus, in the preferred embodiments of the present invention, an entire area of each of the cut lines and corresponding location on the mother substrate are covered by a cover material except only for portions of intersection with other cut lines. Also, there is no need for size reduction of the elements, such as thin film coil patterns, in the preferred embodiments of the present invention, as is required in the method shown in FIG. 5.
Further, the method according to the preferred embodiments of the present invention reliably and accurately avoid the problems shown in FIG. 7 of debris being created during the dicing process, while ensuring a sufficiently large size of the elements of the electronic component.
Also according to the preferred embodiments of the present invention, the dicing process represents a concept signifying a method of gradually cutting the mother substrate by a machining process including bringing a rotating blade (dicing blade) into contact with the mother substrate. It is important to note that no particular restriction is imposed on the kinds of the dicing blade or cutting blade or process used for the first and second cutting steps.
Further, the method of manufacturing an electronic component according to preferred embodiments of the present invention includes a step wherein a conductor pattern is arranged on the surface of the mother substrate and the surface of the mother substrate where the conductor pattern is arranged is covered with the cover material, such as an insulating film and/or a protective film.
When the preferred embodiments of the present invention are applied to a method of manufacturing an electronic component (for example, a chip type coil part where a coil pattern is arranged on the surface) which requires a step of cutting a mother substrate where a conductor pattern (for example, coil pattern) is arranged on the surface and the surface arranged with the conductor pattern is covered with the over material (for example, insulating/protecting film), an increased area of sufficient size that is available for use for forming elements, such as a thin film coil pattern, on the surface of the mother substrate can be reliably and accurately provided and an electronic component having a desired function can efficiently be manufactured.
Further, the preferred embodiments of the present invention is naturally applicable to an electronic component where an electrode is arranged at an inside portion of the substrate.
Further, a method of manufacturing an electronic component according to preferred embodiments of the present invention includes the step of forming a cover material comprising an insulating film or a protecting film of a resin group on selected portions of the surface of the substrate.
Although there are cases where a material of an inorganic group such as glass group or the like is used as cover material, a cover material of a resin group is preferably used in the preferred embodiments of the present invention. The cover material of a resin group is softer and more deformable than the material for constituting the mother substrate and debris of the cover material is liable to occur in the step of cutting the mother substrate. However, the occurrence of debris of the cover material of a resin group can efficiently be prevented by applying the steps of preferred embodiments of the present invention.
Further, the method of manufacturing an electronic component according to preferred embodiments of the present invention includes a step wherein exposed portions of the mother substrate at the intersection portions of the cut lines are arranged and adapted to function as cut markers for determining cut positions.
When the exposed portion of the mother substrate is utilized as the cut marker for determining the cut position, a step of separately arranging a positioning marker is eliminated and the mother substrate can efficiently be cut reliably and accurately at predetermined positions without increasing the cost.